[NFC] TypeCheckProtocol: 'AbstractTypeWitnessKind' is no longer useful

Author: AnthonyLatsis

lib/Sema/TypeCheckProtocol.h

@@ -100,52 +100,26 @@ CheckTypeWitnessResult checkTypeWitness(Type type,
                                         const NormalProtocolConformance *Conf,
                                         SubstOptions options = None);
 
-/// Describes the means of inferring an abstract type witness.
-enum class AbstractTypeWitnessKind : uint8_t {
-  /// The type witness was inferred via a same-type-to-concrete constraint
-  /// in a protocol requirement signature.
-  Fixed,
-
-  /// The type witness was inferred via a defaulted associated type.
-  Default,
-
-  /// The type witness was inferred to a generic parameter of the
-  /// conforming type.
-  GenericParam,
-};
-
 /// A type witness inferred without the aid of a specific potential
 /// value witness.
 class AbstractTypeWitness {
-  AbstractTypeWitnessKind Kind;
   AssociatedTypeDecl *AssocType;
   Type TheType;
 
-  /// When this is a default type witness, the declaration responsible for it.
-  /// May not necessarilly match \c AssocType.
+  /// The defaulted associated type that was used to infer this type witness.
+  /// Need not necessarilly match \c AssocType, but their names must.
   AssociatedTypeDecl *DefaultedAssocType;
 
-  AbstractTypeWitness(AbstractTypeWitnessKind Kind,
-                      AssociatedTypeDecl *AssocType, Type TheType,
-                      AssociatedTypeDecl *DefaultedAssocType)
-      : Kind(Kind), AssocType(AssocType), TheType(TheType),
+public:
+  AbstractTypeWitness(AssociatedTypeDecl *AssocType, Type TheType,
+                      AssociatedTypeDecl *DefaultedAssocType = nullptr)
+      : AssocType(AssocType), TheType(TheType),
         DefaultedAssocType(DefaultedAssocType) {
     assert(AssocType && TheType);
+    assert(!DefaultedAssocType ||
+           (AssocType->getName() == DefaultedAssocType->getName()));
   }
 
-public:
-  static AbstractTypeWitness forFixed(AssociatedTypeDecl *assocType, Type type);
-
-  static AbstractTypeWitness forDefault(AssociatedTypeDecl *assocType,
-                                        Type type,
-                                        AssociatedTypeDecl *defaultedAssocType);
-
-  static AbstractTypeWitness forGenericParam(AssociatedTypeDecl *assocType,
-                                             Type type);
-
-public:
-  AbstractTypeWitnessKind getKind() const { return Kind; }
-
   AssociatedTypeDecl *getAssocType() const { return AssocType; }
 
   Type getType() const { return TheType; }

lib/Sema/TypeCheckProtocolInference.cpp

@@ -44,25 +44,6 @@ STATISTIC(NumDuplicateSolutionStates,
 
 using namespace swift;
 
-AbstractTypeWitness AbstractTypeWitness::forFixed(AssociatedTypeDecl *assocType,
-                                                  Type type) {
-  return AbstractTypeWitness(AbstractTypeWitnessKind::Fixed, assocType, type,
-                             nullptr);
-}
-
-AbstractTypeWitness
-AbstractTypeWitness::forDefault(AssociatedTypeDecl *assocType, Type type,
-                                AssociatedTypeDecl *defaultedAssocType) {
-  return AbstractTypeWitness(AbstractTypeWitnessKind::Default, assocType, type,
-                             defaultedAssocType);
-}
-
-AbstractTypeWitness
-AbstractTypeWitness::forGenericParam(AssociatedTypeDecl *assocType, Type type) {
-  return AbstractTypeWitness(AbstractTypeWitnessKind::GenericParam, assocType,
-                             type, nullptr);
-}
-
 void InferredAssociatedTypesByWitness::dump() const {
   dump(llvm::errs(), 0);
 }
@@ -882,8 +863,7 @@ AssociatedTypeInference::computeDefaultTypeWitness(
   if (defaultType->hasError())
     return None;
 
-  return AbstractTypeWitness::forDefault(assocType, defaultType,
-                                         defaultedAssocType);
+  return AbstractTypeWitness(assocType, defaultType, defaultedAssocType);
 }
 
 std::pair<Type, TypeDecl *>
@@ -920,7 +900,7 @@ AssociatedTypeInference::computeAbstractTypeWitness(
   // We don't have a type witness for this associated type, so go
   // looking for more options.
   if (Type concreteType = computeFixedTypeWitness(assocType))
-    return AbstractTypeWitness::forFixed(assocType, concreteType);
+    return AbstractTypeWitness(assocType, concreteType);
 
   // If we can form a default type, do so.
   if (const auto &typeWitness = computeDefaultTypeWitness(assocType))
@@ -930,7 +910,7 @@ AssociatedTypeInference::computeAbstractTypeWitness(
   if (auto genericSig = dc->getGenericSignatureOfContext()) {
     for (auto gp : genericSig.getInnermostGenericParams()) {
       if (gp->getName() == assocType->getName())
-        return AbstractTypeWitness::forGenericParam(assocType, gp);
+        return AbstractTypeWitness(assocType, gp);
     }
   }